Method and System for Processing Write Requests

1. A machine implemented method for writing data at a storage device, comprising: receiving a write command from an initiator adapter coupled to a host system by a first peripheral link at a target adapter, interfacing with a target controller by a second peripheral link, for writing data to the storage device; wherein the target controller is a computing device that manages the storage device, and wherein the write command from the initiator adapter is received at the target adapter using a network connection and includes information regarding a virtual logical unit number (LUN) for writing data in response to the write command; notifying a target driver by the target adapter to accept the write command from the initiator adapter, the target driver executed by the target controller; in response to the notification, mapping LUN information by the target driver to identify a physical LUN for storing the data at the storage device in response to the write command, the target driver using a data structure stored at the target adapter to perform the mapping; notifying the target adapter by the target driver to process the write command and providing to the target adapter by the target driver, information regarding the physical LUN and a write back flag; sending by the target adapter, via the network connection, a response to the initiator adapter indicating that the target adapter is ready to receive data for the write command and in response to the write back flag, simultaneously issuing a write command for the physical LUN to the storage device before any data is received from the initiator adapter for the write command sent by the initiator adapter to the target adapter; receiving data from the initiator adapter for the write command at the target adapter and an indicator from the storage device that the storage device is ready to write the data to the physical LUN; transferring the received data from the initiator adapter to a memory of the target controller via a direct memory access (DMA) operation and simultaneously also sending the data to the storage device for the physical LUN in response to the indicator received from the storage device; and sending via the network connection, a completion message to the initiator adapter by the target adapter, before receiving any completion message from the storage device that writes the data.

2. The method of claim 1 , wherein the write command is a small computer systems interface (SCSI) command sent using a Fibre Channel protocol.

3. The method of claim 1 , wherein the write command is a small computer systems interface (SCSI) command sent using a Fibre Channel over Ethernet protocol.

4. The method of claim 1 , wherein the initiator adapter is a Fibre Channel over Ethernet converged adapter.

5. The method of claim 1 , wherein the target adapter is a Fibre Channel over Ethernet converged adapter.

6. The method of claim 1 , wherein the initiator adapter is a Fibre Channel adapter.

7. The method of claim 1 , wherein the target adapter is a Fibre Channel adapter.

8. A system comprising: a host computing system coupled to an initiator adapter by a first peripheral link; and a target adapter using a second peripheral link for interfacing with a target controller for writing data to a storage device, the target controller executing a target driver and the initiator adapter and the target adapter communicating via a network connection; wherein the target controller is a computing device that manages the storage device; wherein the target adapter receives a write command from the initiator adapter via the network connection for writing data to the storage device, where the write command includes information regarding a virtual logical unit number (LUN) for writing data in response to the write command, and wherein the target adapter notifies the target driver to accept the write command from the initiator adapter; wherein the target driver, in response to the notification, uses a data structure at the target adapter maps LUN information to identify a physical LUN for storing the data at the storage device in response to the write command; and notifies the target adapter to process the write command with information regarding the physical LUN and a write back flag; and wherein the target adapter: sends a response to the initiator adapter via the network connection that the target adapter is ready to receive data for the write command and in response to the write back flag, simultaneously issues a write command for the physical LUN to the storage device before any data is received from the initiator adapter for the write command sent by the initiator adapter; receives data from the initiator adapter for the write command and an indicator from the storage device that the storage device is ready to write the data to the physical LUN; transfers the received data from the initiator adapter to a memory of the target controller via a direct memory access (DMA) operation and simultaneously also sends the data to the storage device for the physical LUN in response to the indicator received from the storage device; and sends via the network connection, a completion message to the initiator adapter before receiving any completion message from the storage device that writes the data.

9. The system of claim 8 , wherein the write command is a small computer systems interface (SCSI) command sent using a Fibre Channel protocol.

10. The system of claim 8 , wherein the write command is a small computer systems interface (SCSI) command sent using a Fibre Channel over Ethernet protocol.

11. The system of claim 8 , wherein the initiator adapter is a Fibre Channel over Ethernet converged adapter or a Fibre Channel adapter.

12. The system of claim 8 , wherein the target adapter is a Fibre Channel over Ethernet converged adapter or a Fibre Channel adapter.

13. A non-transitory machine readable storage medium having stored thereon instructions for performing a method for writing data at a storage device, comprising machine executable code which when executed by at least one machine, causes the machine to: receive a write command from an initiator adapter coupled to a host system by a first peripheral link at a target adapter, interfacing with a target controller by a second peripheral link, for writing data to the storage device; wherein the target controller is a computing device that manages the storage device, and wherein the write command from the initiator adapter is received at the target adapter using a network connection and includes information regarding a virtual logical unit number (LUN) for writing data in response to the write command; notify a target driver by the target adapter to accept the write command from the initiator adapter, the target driver executed by the target controller; in response to the notification, map LUN information by the target driver to identify a physical LUN for storing the data at the storage device in response to the write command, the target driver using a data structure stored at the target adapter to perform the mapping; notify the target adapter by the target driver to process the write command and provide to the target adapter by the target driver, information regarding the physical LUN and a write back flag; send by the target adapter, via the network connection, a response to the initiator adapter indicating that the target adapter is ready to receive data for the write command and in response to the write back flag, simultaneously issue a write command for the physical LUN to the storage device before any data is received from the initiator adapter for the write command sent by the initiator adapter to the target adapter; receive data from the initiator adapter for the write command at the target adapter and an indicator from the storage device that the storage device is ready to write the data to the physical LUN; transfer the received data from the initiator adapter to a memory of the target controller via a direct memory access (DMA) operation and simultaneously also send the data to the storage device for the physical LUN in response to the indicator received from the storage device; and send, via the network connection, a completion message to the initiator adapter by the target adapter before receiving any completion message from the storage device that writes the data.

14. The non-transitory machine readable storage medium of claim 13 , wherein the write command is a small computer systems interface (SCSI) command sent using a Fibre Channel protocol.

15. The non-transitory machine readable storage medium of claim 13 , wherein the write command is a small computer systems interface (SCSI) command sent using a Fibre Channel over Ethernet protocol.

16. The non-transitory machine readable storage medium of claim 13 , wherein the initiator adapter is a Fibre Channel over Ethernet converged adapter.

17. The non-transitory machine readable storage medium of claim 13 , wherein the target adapter is a Fibre Channel over Ethernet converged adapter.

18. The non-transitory machine readable storage medium of claim 13 , wherein the initiator adapter is a Fibre Channel adapter.

19. The non-transitory machine readable storage medium of claim 13 wherein the target adapter is a Fibre Channel adapter.